The frequency with which an IC, such as, for example, a memory chip, can be accessed is usually an important factor in the overall performance of the system within which that IC is used. Generally, as the speed with which the IC is accessed increases the overall system performance will also increase. Thus, it is desirable to access an IC at or near its highest or maximum access frequency to thereby increase the overall performance of the system within which the IC is being used.
However, as the frequency with which the IC is accessed increases, the power consumed by and, thus, the heat generated by the IC also increases. At least some of the power consumed by the operation of the IC is transferred in the form of heat to the IC die. Thus, in general, as the frequency with which the IC is accessed increases so to does the temperature of the IC die. If the temperature of the die exceeds a recommended and/or maximum threshold, temperature viruses (e.g., data corruption) and/or chip failure may result. To avoid such a condition, IC manufacturers recommend that the IC be operated at a predetermined maximum access frequency. The predetermined maximum access frequency is typically conservative, and is based upon worst-case operating conditions, such as, for example, an ambient temperature and/or a die temperature at or near the respective rated maximums. Because the maximum access frequency rating is based upon such worst case conditions, it may be possible to access the IC at a frequency in excess of the maximum frequency rating when the IC is operating under typical, i.e., less than worst case, conditions. Additionally, when the die temperature is at or approaching the rated maximum it may be necessary to access the IC at frequencies below the maximum access frequency to ensure the IC is consuming less power and thereby enable the die to “cool off”.
Therefore, what is needed in the art is a method and apparatus that adjusts the frequency with which an IC is accessed based upon the die temperature of the IC.
Furthermore, what is needed in the art is a method and apparatus that enables an IC to be accessed with a higher frequency when the die temperature is below a predetermined maximum.
Moreover, what is needed in the art is a method and apparatus that enables an IC to be accessed with a lower frequency when the die temperature is at or approaching a predetermined maximum.